Monday, 10 June 2019

electromagnetism - Biot-Savart law from Ampère's with multivariate calculus


Let us assume the validity of Ampère's circuital law γBdx=μ0Ilinked

where B is the magnetic field, γ a closed path linking the current of intensity Ilinked.


Can the Biot-Savart law B=μ04πId׈rr2=μ04πbaI(t)×x(t)x(t)3dt

where :[a,b]R3 is a parametrisation of a closed (or infinite) wire carrying the current I, be inferred without using Dirac's δ, by using the tools of multivariate calculus and elementary differential geometry only, at least if we assume the validity of the Gauss law for magnetism or other of the Maxwell equations? All the proofs I have found (such as this, where, as far as I understand, 2[μ04πJ(r)|rr|d3r]=μ0J(r)
is derived by using the δ) use the expression B=μ04πVJ׈rr2d3x
and Dirac's δ, but I wonder whether, both assuming a linear current distribution as when we use the expression of the magnetic field asB=μ04πId׈rr2
and assuming a tridimensional spatial current distribution, it is possible to prove the Biot-Savart law from Ampère's without the use of the δ. I heartily thank any answerer.




No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...